Moving gas panel display system

ABSTRACT

A gas panel display system produces a moving display as a result of movement of at least one set of conductors. A first set of parallel conductors aligned parallel to the direction of motion of the display image is mounted behind a display window in a gas tight display housing which contains an ionizeable gas. A second perpendicular set of parallel conductors insulated from the ionizeable gas is mounted on a moving belt which carries the display image past the window. Information is written into the display by applying ignition pulses to a set of writing electrodes aligned along a line parallel to the conductors of the second set. The ignition pulses ionize the gas between the writing electrodes and the second conductors, thereby creating activated display points along the second conductors. The information written into the activated display points is made visible by applying a sustaining voltage between the conductor sets to sustain a glow discharge in the ionizeable gas at the activated points. An erase roller located just before the writing electrodes erases any remaining, previously written, information.

Apr. 24, 1973 United States Patent 41 Konnerth et al.

[57] ABSTRACT A gas panel display system produces a moving displayMOVING GAS PANEL DISPLAY SYSTEM as a result of movement of at least oneset of conductors. A first set of parallel conductors a] igned parallelto the direction of motion of the display image is mounted behind adisplay window in a gas tight dis- Corporation, Armonk, N .Y.

June 23, 1971 [21] Appl. No.: 155,970

play housing which contains an ionizeable gas. A

second perpendicular set of parallel conductors insu- [22] Filed:

' lated from the ionizeable gas is mounted on a movm W pp y s belt whichcarries the display image past the windo Information is written into thedisplay by a nition pulses to a set of writing electro 5 0 4 0 L mm 0 ,4M3 R 2 3w a m 3 5m m3m w C S t U h l l. 2 l 5 5 .l l

des aligned along a line parallel to the conductors of the second set.The ignition pulses ionize the gas between the writing electrodes andthe second conductors, thereby [58] Fleld of Search creating activateddisplay points along the second con- 340/343 324 M; g 3 325;: ductors.The information written into the activated display points is madevisible by applying a sustaining voltage between the conductor sets tosustain a glow [56] References Cited discharge in the ionizeable gas atthe activated points.

An erase roller located just before the writing electrodes erases anyremaining, previously written, information.

UNITED STATES PATENTS .....3l3/l47 X Coleman etal...................340/324 R 13 Claims, 15 Drawing Figures Gestelandet al.

Primary Examiner-David L. Trafton Attorney-Maurice H. Klitzman et al.

MOTOR CONTROL ENERGlZlNG MEANS Patented A ril 24, 1913 6 Sheets-Sheet 1INVENTORS KARL L KONNERTH CONRAD LANZA ATTORNEY s Sheets- Sheet sPatented April 24, 1973 FIG WRITING VOLTAGE SUSTAINING 0 VOLTAGE plays.

1 MOVING GAS PANEL DISPLAY SYSTEM BACKGROUND OF THE INVENTION 1. Fieldof the Invention The invention relates to the field of electronicallychangeable information displays, and more particularly to the field ofmoving electronically changeable information displays.

2. Description of the Prior Art Modern changeable information displaysare preferably self-illuminated to assure easy reading of the displayedinformation independent of the level of general illumination in thevicinity of the display. To assure reliable, long life displays,electronic control over the characters to be displayed is preferred tomechanical control.

Stationary gas panel displays as well as non-gas panel moving displaysare well-known in the art. The stationary gas panel displays arecomprised of two sets of parallel conductors arranged perpendicular toeach other, so that one set determines the X coordinates and the otherset determines the Y coordinates of display points. In order to sustaindesired glow discharges, a sustaining voltage is applied between the Xand Y c'onductors. The magnitude of this voltage must be closely 1controlled so that the voltage between the X and Y conductors atthepoints where they cross is sufficient to sustain glow dischargeswhich are already in existence, but not so great as to initiate newdischarges. A new glow discharge at a selected point is produced byapplying half select write voltages to each of the corresponding X and Ylines. These half select write voltages must be closely controlled inamplitude, frequency and timing, in order to assure that the selectedglow will be initiated and that no other glows will be initiated. Thesedisplays have the disadvantage that they require one driver for each Xline and one driver for each Y line of the display.

Among the known moving displays are those comprised 'of many individuallight bulbs which are sequentially illuminated to create the illusion ofmoving characters and changeable mechanical movingbelt dis- Today,particularly in small displays, bulbs are in disfavor because of thepower'required to illuminate them and because of the high powerswitching circuitry necessary for their operation.

One type of prior art mechanical moving belt display is comprised of amatrix in which-each element has two sides of differing colors. Amessage is written on the belt by turning selected elements of thematrix around to form the desired characters on the viewing face of thematrix. Such displays, unfortunately, are subject to the usualreliability problems of systems containing many moving parts and are notcapable of providing self-illuminated displays with electronic controlof the characters to be displayed.

OBJECTS OF THE INVENTION The primary object of the invention is toself-illuminate a moving display.

Another object is to provide a moving gas panel display.

Another object of the invention is to stop or reverse a moving gas paneldisplay.

individual light An additional object is to provide a writable gas paneldisplay without requiring close tolerances on the write signals.

A further object of the invention is to provide a gas panel displaysystem with a greatly reduced number of write drivers.

Still another object of the invention is to provide a gas panel displaysystem in which the write signals amplitude, frequency and timing areindependent of the sustaining voltage.

SUMMARY OF THE INVENTION The above objects are accomplished by a gaspanel I display system in which a first set of preferably paralleltransparent conductors aligned parallel to the direction of motion ofthe display is mounted on the inside of a viewing window and a secondperpendicular set of parallel conductors is carried past the viewingwindow in a first direction by an endless belt. A display point islocated where a conductor from the first set and a conductor from thesecond set intersect. An insulating layer is interposed between thefirst conductors and the second conductors. The insulating layer isprovided so that a writing station located just upstream of the windowcan activate selected display points along the second conductors bydepositing a memory charge on the insulation. Ignition pulses ofsufficient voltage to ionize the gas between writing electrodes and thesecond conductors are applied to selected writing electrodesalignedalong a line parallel to the second conductors to activate correspondingdisplay points on the belt. Displayed information is made visible byapplying a sustaining voltage between the first and second sets ofconductors to support a glow discharge of the ionizeable gas at eachactivated display point. The insulating layer moves with the secondconductors to transport the memory charge and thus the displayedinformation past the window. The writing electrodes are separated fromthe first set of parallel conductors to insulate the ignition pulsesfrom the effect of the sustaining voltage and to render the sustainingand writing voltages independent. Undesired information is erased fromthe display be a conducting erase r'oller in contact with the endlessbelt just upstream from the writing station.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiments of the invention, asillustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Q FIG. 1 is a perspective view of thedisplay unit and a block diagram of the control system.

FIG. 2 is a partially cut-away view of a section of the endless belt andthe electrical contacts to it. 7

FIG. 3 is a perspective detail showing the writing station, the viewingwindow, and the erase roller.

FIG. 4 is a section view of the writing structure taken along the line44 in FIG. 3.

FIG. 5 illustrates the writing and sustaining voltages.

' FIGS. 6 through 14 are a step by step illustration of the writing intothe display of the letter'A and the first part of the letter B. 1

FIG. 15 is a timing diagram showing the sequence of operations inwriting the letter A and B in FIGS. 6-14.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A moving gas paneldisplay unit is shown in FIG. 1. The unit comprises a housing means 102having a viewing window 104. A first plurality of parallel conductors108 is disposed behind the viewing window 104 with conductors 108preferably aligned parallel to the direction of the display motion.Conductors 108 are preferably transparent and mounted on the back ofwindow 104. The individual conductors 108 are connected together by acommon conductor 110. The common conductor 110 is connected to anenergizing means 195 which supplies a sustaining voltage 212 (FIG.through wire 112.

The energizing means 195 can generate the sustaining signal or cantransform a signal such as a line voltage to an appropriate voltagelevel.

A translating means is disposed behind window 104 within housing 102 fortranslating a second plurality of parallel conductors 132 past theviewing window 104 to create a moving display. The transport means iscomprised of an endless belt 122 and a drive means for revolving thebelt. The drive means comprises a pair of belt support rollers 150 and152, a motor 156 for driving the belt and a magnetic clutch 154 throughwhich motor 156 drives roller 152 to drive the belt. The motor 156 iscontrolled by a motor control 196 through cable 158. Motor control 196controls the speed and direction of display movement in accordance withcontrol signals received on cable 197. The rotation of motor 156 istransmitted to driven roller 152by a magnetic coupling 154. One of theelements of coupling 154 is inside the gas tight housing 102 and theother is outside thus enabling the rotation to be transmitted to roller152 without requiring expensive rotary vacuum seals. Belt 122 isnormally driven past window 104 from right to left, since the display isintended to be read from left to right.

The structure of the belt 122 is best seen in FIG. 2. The-belt iscomprised ofa backing layer 124 and a front layer 126. The secondplurality of conductors 132 is preferably disposed perpendicular to thedirection of motion of belt 122 and between the layers of the belt. Adisplay point is created where a conductor 108 from the first set and aconductor 132 from the second set intersect. Throughout thisspecification'theterm intersection is used to mean a point whereconductors of the different sets cross over each other. The individualconductors 132 are connected together by a common conductor 134 having aconnecting land 136 extending between the layers of the belt. Connectingland 136 is preferably bent around the bottom and up the back of backlayer 124. The part of the connecting land 136 on the back of the backlayer is preferably separated into discrete tooth-like timing bars 138having the same spacing as the conductors 132. A connector brush 140 isattached to housing 102 and makes continuous contact with the connectingland 136. The brush 140 is connected to the grounded input of energizingmeans 195 by wire 142.

A writing means 160 for activating selected display points alongconductors 132 of the second set of conductors is disposed just to theright of the viewing window because the display unit is intended ,forright to left movement of the displayed characters. Writing means 160 isbest seen in FIGS. 3 and 4. The writing means is comprised of aplurality of writing electrodes 171-177, one associated with eachconductor 108 in the first set. The conductors 108 do not extend as faras the writing electrodes 171-177, but each writing electrode is on thesame straight line as its associated conductor 108. Writing electrodes171-177 are supported by write station support 162 and each electrode isconnected by cable 167 to a gated amplifier which controls the writingelectrode in a manner to be explained hereinafter. For convenience ofthe drawings, the display unit is shown as having seven conductors inthe first set and correspondingly seven writing electrodes which arenumbered 171-177 for clarity in referring to them hereinafter. Writingelectrodes 171-177 are connected to amplifiers 201-207, respectively.Selected display points on the belt 122 are activated by applyingignition pulses to the writing electrodes 171-177 corresponding to thosedisplay points. The ignition pulses must be of sufficient amplitude toionize the ionizeable gas between the writing electrodes and the belt,but not so large that the ionization spreads excessively. To assure thatonly the desired points will be activated, the conductors 108 areterminated so that two display points are interposed between a displaypoint under the end of a conductor 108 and a display point under thecorresponding writing electrode. This prevents the ignition pulse fromionizing the gas directly between the writing electrode and thecorresponding conductor 108 from the first set. The alignment of thewriting electrodes 171-177 with the corresponding conductors 108 is moreclearly shown in FIG. 4 which is a section view taken along line 44 inFIG. 3. A writing control means (FIG. 1) contains a plurality of gatedamplifiers 201-207, one for each writing electrode 171-177 and acharacter generator 200 which controls the gating of these amplifiers.Character generator 200 decodes character information received on cable197 into the control signals necessary for writing the desiredcharacter. Each amplifier is connected to ignition pulse generator means104 and when activated by character generator 200 amplifies ignitionpulses produced b generator 194 and transmits the pulses to thecorresponding writing electrode. Character generator 200 has one outputfor controlling each amplifier. The output is a logical one if thecorresponding amplifier is to be activated and a logical zero if theamplifier is not to be activated. Character generators performing thisfunction are well-known in the art and will not be further describedherein since we have not invented a new character generator.

A timing means controls the pulse generator 194 to restrict theapplication of ignition pulses 210 to the writing electrodes to timeswhen a conductor 132 from the second set of conductors is in alignmentwith the electrodes 171-177. This timing means is comprised of a sensemeans and a timing control means 192. The sense means is comprised of asensor brush 146 supported by housing 102 for contacting timing bars 138on the back of belt 122, however it will be understood that anyalignment sensing means, including optical means may be used. Sensorbrush 146 is connected to timing control 192 by a wire 148. Sense brush146 senses alignment between a conductor 132 from the second set ofconductors and .writing electrodes 171-177 by making contact with atiming bar 138 on the back of belt 122. Timing control 192, responsiveto sense brush 146 contacting timing bar 138, triggers ignition pulsegenerator 194. Those amplifiers of amplifiers 201-207 which are beingheld in an on condition by character generator 200 amplify the ignitionpulse and transmit it to the corresponding writing electrodes 171-177.When sense brush 146 loses contact with a timing bar 138, timing control192 triggers character generator 200 to advance to its next state. Thecharacter generator upon advancing to its next state supplies newoutputs for controlling the amplifiers in accordance with the nextvertical line to be written. In this manner, pulse generator 194 andcharacter generator 200 are triggered alternatively as sense brush 146contacts successive timing bars 138.

An erase means deactivates previously activated display points prior tothe writing of new information onto the display. The erase means iscomprised of an erase roller 180 supported in contact with the frontlayer 126 of belt 122 by an axle 182. The erase roller 180 has aconductive surface which is connected by contact brush 184 and wire 142to contact brush 140. The erase roller 180 deactivates previouslyactivated points by neutralizing the charge stored on the belt as thebelt moves past the roller. Contact brush 184 and wire 142 connectroller 180 to the second conductors 132 through brush 140 to assure thatconductors 132 and roller 180 are at the same potential, thus assuringcomplete removal of charges from the belt.

A typical writing voltage 210 and a typical sustaining voltage 212 areshown in FIG. 5. The amplitudes of these voltages will depend on thespacing of the electrodes and conductors and on the dielectriccharacteristics of the front layer 126 of belt 122. The foregoinginvention and its advantages will be more fully understood from thefollowing explanation of the operation of the invention.

OPERATION OF A PREFERRED EMBODIMENT OF THE INVENTION Operation of thedisplay system is initiated by energizing motor 156 to drive belt 122.As shown in FIG. 1, the belt is driven to pass the 'display window fromright to left. The energizing means 195 is also energized to impress asustaining voltage such as is shown in FIG. 5 on the first conductorset, the second conductor set being grounded. As the belt 122 passes theerase means 180, any memory charges remaining on the belt are removed todeactivate all display points. The display is now ready to begindisplaying information. Each time sense brush 146 contacts a timing bar138 on the back layer 124 of belt 122, the ignition pulse generator 194is triggered as is shown in FIG. 15. Until a control signal is receivedon cable 197 by the character generator 200, all of the gated amplifier201-207 will be turned off and the ignition pulse will not be passed toany of the writing electrodes 171-177'. After receipt of a character oncable 197, the next character generator trigger pulse from timingcontrol 192 in response to sensor brush 146 losing contact with a timingbar 138 will cause the character generator to activate those amplifierscorresponding to the display points to be activated in the firstvertical line of the letter.

For simplicity of the description of the operation of the display, thedisplay is shown one character high.

The characters are written at the right hand edge of the display window104 and move across window 104 from right to left at a constant speedand disappear from view at the left hand edge of the window. Theconstant speed is provided by continuously energizing motor 156 torotate drive roller 152 and the display belt 122 continuously. When aconductor 132 on the endless belt is adjacent to the writing electrodes171-177, the sense brush 146 makes contact with one of the timing bars138 on belt 122 and the timing control 192 triggers the ignition pulsegenerator 194. The ignition pulse is amplified by those amplifiers whichhave been activated by character generator 200. The amplified ignitionpulses 210 are applied to the corresponding writing electrodes 171-177by the multiple conductor cable 167. The amplitude of the amplifiedignition pulses is large enough to ionize the gas between the selectedwriting electrodes and belt 122. With a negative ignition pulse 210 asshown in FIG. 5, electrons from the ionized gas are attracted to belt122 and positive ions of the gas are attracted to writing electrodes171-177. Since the front surface 126 of belt 122 is insulating, theelectrons attracted to belt 122 remain on the belt as static charges.The ions attracted to writing electrodes 171-177 obtain electrons fromthe elec trodes and are deionized. Once ignition pulse 210 is removed,the ionization of the gas between the writing electrodes 171-177 andbelt 122 ceases. However, the charge on belt 122 remains and moves withthe belt, thereby serving as a memory element which activates thedisplay point in accordance with the outputs of the character generator200. 1

A visible glow is produced behind viewing window 104 by the sustainingvoltage 212 which is applied to the conductors 108 on the back of window104. As has been explained, the amplitude of sustaining voltage 212 mustbe high enough to initiate a glow discharge at each activated point, butnot so high as to initiate discharges at non-activated points. As theactivating memory charges on the belt move behind conductors 108 onwindow 104, sustaining voltage 212 re-excites the glow discharge in amanner explained hereinafter.

During each half cycle of the sustain voltage, an electric field isdeveloped between the conductors 108 and the conductors 132 through theionizeable gas however, this field is not strong enough to ionize thegas in the absence of an activating charge. If sustaining voltage 212 ison a negative half cycle when the negative activating charge on belt 122comes under the influence of sustaining voltage 212 there is noionization effect until the succeeding half cycle. During the firstpositive half cycle of sustaining voltage 212 to which a negative chargeon belt 122 is subjected, an electric field is built up from conductor108 on the back of viewing window 104 to the negative charge on belt122. This field is of sufficient strength to ionize the gas betweenconductor 108 and the charge on belt 122. The ionization of the gasreleases positive ions and negative electrons. The electrons areattracted to the conductor 108 by its positive voltage and the ions areattracted to belt 122 by its negative charge. At the end of the positivehalf cycle a positive charge is left on belt 122, either due to theattraction and retention of positive ions on the belt or due to theattraction of positive ions to the belt and their extraction ofelectrons from the belt, leaving a positive static charge on belt 122.On the subsequent negative half cycle of sustain voltage 212, the fieldbetween conductor 108 and the positive charge on belt 122 ionizes thegas between the conductor and the charge on the belt. This time positiveions are attracted to conductor 108 and the electrons are attracted tobelt 122 and a negative charge is left on the belt at the end of thenegative half cycle. The ionization of the gas under the influence ofsustaining voltage 212 and a charge on the belt repeats this patternindefinitely. Thus, during each half cycle of sustaining voltage 212,the sign of the charge on belt 122 reverses.

As belt 122 moves past display window 104 the glow discharge associatedwith an activated point on the belt moves continuously along the window,because in the preferred embodiment conductors 108 on window 104 areparallel to the direction of motion which enables the glow discharge toretain the shortest distance between conductor 108, and the activatedpoint on belt 122, thus following the display point. If the orientationof the two sets of conductors were reversed so that the stationaryconductors 108 were perpendicular to the direction of motion to thedisplay, the glow discharges constituting the display would appear tojump from one conductor on window 104 to the next and could be subjectto spreading of the ionization and a consequent destruction of theinformation being displayed.

The cooperation of sustaining voltage 212 and the charges on belt 122retains the configuration of activated points on the belt. The displayedinformation therefore moves across window 104 at the same rate as belt122. Once an activated point on belt 122 moves out from under theinfluence of sustaining voltage 212 on conductors 108, the glowdischarge at that display point ceases. The charge on belt 122 willslowly dissipate once the charge is no longer under the influence ofsustaining voltage 212. However, some of the charge would normallyremain when that point on belt 122 returns to the writing station 162 tobe written with new information. The presence of this charge wouldresult in improper writing by the writing means 160. For this reasonthe'erase means (roller 180) is placed just to the right of the writingmeans to remove charges remaining on the belt and thus assure that allthe display points are deactivated before they reach the writing station162.

To illustrate the writing of characters into the display, the writing ofa letter A and the first part of a letter B in a X 7 character formatwill be followed step-by-step in FIGS. 6-14. FIG. is a timing diagramshowing the sequence of events in the writing of these characters andshows the timing of (I) sense brush 146's output, (2) the pulsegenerator trigger, (3) the character generator trigger and (4) thechanges in the amplifier control signals produced by character generator200. Referring to FIG. 15 throughout the following discussion will aidin comprehension. Now referring to FIG. 6, the location of the writingsite is indicated by the arrow marked 162. The location of the sevenvertical display points are indicated by the positions of the amplifiers201-207 to the right of the writing site. The amplifiers which areactivated by the character generator are shown in black. The unactivatedamplifiers are shown in outline. The ionization created by the amplifiedignition pulse at each selected display point is indicated by the symbolshown at 220 in FIG. 6. The symbol for an activated display point whichhas not reached a conductor 108 and thus is not the site of a presentglow discharge is shown at 222 in FIG. 7. The symbol for a glowdischarge at a activated point in response to sustaining voltage 212 isshown at 224 in FIG. 9.

The writing of the character A is begun by the character generator 200receiving an electronic symbol for character A on cable 197 as shown inFIG. 15. Subsequently the sense brush 146 loses contact with a timingbar 138 on the back of belt 122 and timing control 192 supplies acharacter generator trigger to character generator 200. In response tothe character generator trigger, the character generator 200 activatesthose amplifiers corresponding to display points to be activated in thefirst line of the letter A. (A This is shown in FIG. 6 where amplifiers202 through 207 are activated. When sense brush 146 makes contact withthe next timing bar 138, one of the conductors 132 in belt 122 isaligned with the writing electrodes 171-177 (write station 162). Thecontacting of timing bar 138 by brush 146 causes timing control 192 totrigger ignition pulse generator 194. Each activated amplifier 202-207amplifies the ignition pulse and applies it to the corresponding writingelectrodes 172-177. In response to the ignition pulses on writingelectrodes 172-177, the gas between each of these electrodes and belt122 ionizes and'deposits an activating negative charge on belt 122. Theionization of the gas at these points is indicated in FIG. 6 by thesymbols at 220. After the ignition pulses cease, the ionization betweenwriting electrodes 172-177 and belt 122 ceases and activated displaypoints corresponding to the previous ionization remain as shown in FIG.7. Brush 146 subsequentially loses contact with that timing bar 138causing timing control 192 to trigger character generator 200 whichchanges the state of the amplifiers to that shown in FIG. 7 where onlyamplifiers 201 and 204 are activated. On the next contact of brush 146with a timing bar, the next conductor 132 is aligned with the writingelectrodes and an ignition pulse is generated. Ignition pulse 210 isamplified by amplifiers 201 and 204 and applied to writing electrodes171 and 174 causing the ionization of gas between electrodes 171 and 174and belt 122 as shown in FIG. 7. As shown in FIG. 7, the previouslyactivated display points corresponding to the first line of the letter Aare not yet under the influence of the sustaining voltage 212 andtherefore do not have glow discharges associated with them. This lack ofionization is to prevent the spreading of the ionizations caused by theignition pulses 210 which would obscure desired information and writeerroneous information. Once the gas between electrodes 171 and 174 andbelt 122 is ionized, ignition pulse 210 ceases and the ionization ceasesand activated display points corresponding to the ionizations remain asshown in FIG. 8. Sense brush 146 loses contact with that timing bar 138causing character generator 200 to activate amplifiers in accordancewith the third line (A of the letter A. The

third line of the letter A is identical to the second line and thereforeno change in the state of the amplifiers takes place. As can be seen inFIG. 8, once again, writing electrodes 171 and 174 corresponding toamplifiers 201 and 204 activate display points on belt 122. The

operation of the display continues in the same fashion. As shown in FIG.9 for the fourth line of letter A, am plifier 201 and 204 are activatedthus activating the corresponding display points on belt 122. As shownin FIG. 9, when the belt is in position for the writing of the fourthline (A of the letter A, the first line (A,) of the letter A has comeunder the influence of sustaining voltage 212 on conductors 108 and theactivated display points in the first line have been re-excited in themanner explained above.

In FIG. 10, the amplifiers are shown activated for the writing of thefifth and last line of letter A. Amplifiers 202-207 are activated toactivate the corresponding display points. Here both the first andsecond lines of letter A are under the influence of sustaining voltage212 on conductors 108 and therefore have been reexcited and glow tocreate a visible display. As shown in FIG. 11, no amplifiers areactivated for the first line following letter A, in order to provide aspace between the letter A and the subsequent letter (B). At this point,the first three lines of letter A are creating a visible display. InFIG. 12, the first four lines of the letter A are shown creating avisible display and the amplifiers are all shown unactivated to leave asecond displayless line separating letter A from letter B. In FIG. 13,the entire letter A is creating a visible display and the amplifiers201-207 are shown activated for writing the first line of letter B. InFIG. 14, the letter A is completely visible as it was in FIG. 13. Theactivated display points for the first line of letter B are shown inFIG. 14 and the amplifiers are shown activated for writing the secondline of letter B. Amplifiers 201 and 204 and 207 are activated in orderto activate the corresponding display points. The writing of letter Band other characters proceeds in the above fashion.

The display system of the invention provides many benefits. First, thedisplay is a self-illuminated moving display. Second, the tolerances onthe writing voltage is more relaxed then in stationary gas panel displaysystems using half-select writing because at the time that a displaypoint is activated by an ignition pulse the displaypoint is not underthe'influence of the sustaining voltage and therefore the sustainingvoltage cannot support a spread of the ionization caused bythe ignitionpulse. Therefore, the ignition pulse 210 can be larger than it could bein the presence of the sustaining signal 212. Because the sustainingsignal is not in the vicinity of the ignition pulse, the ignition pulsedoes not need to be coordinated in frequency, amplitude or time with thesustaining voltage.

If desired, the display can be stopped by de-energizing motor 156. Thedisplay can even be backed up by running motor 156 backward, if it isdesired to remove an erroneous letter. As the display backs up, the beltwill carry the erroneous letter under erase roller 180 which will removethe erroneous letter. The motor is then re-energized and the properletter can be written as the belt moves in the forward direction. Thespeed of the display can be varied at will by varying the speed of motor156. The use ofa DC motor makes control of the speed of the motor quitefeasible. By providing a motor speed control on the display panel theviewer can control the rate at which information is displayed, thus afast reader can speed the display up to obtained a maximum amountofinformation in a minimum time.

The display of this invention, when run at high speed, will be easier toread than displays having sequentially illuminated bulbs or spotsbecause the glow discharge in this invention moves continuously,smoothly and without jumping along conductors 108 on window 104 as hasbeen explained above.

Many variations can be made in the above preferred embodiment. If it isdesired to have a bi-directional display, information may be writteninto the display from either direction by providing a second writingstation at the left hand edge of window 104. In another variation in thewriting system all displayed points in alignment with the writingelectrodes 162 could be activated simultaneously and the non-desireddisplay points thereafter selectively erased, Although this method isnot preferred, it is deemed to be within the scope of the attachedclaims.

Although for convenience of description, the preferred embodiment wasshown displaying a single line of characters, any number of lines can bedisplayed by such a system and the number of display points used in thedisplay of a character depends only on the number of lines available andthe versatility of the character generator.

While the invention has been particularily shown and described withreference to a preferred embodiment and variations thereof, it will beunderstood by those skilled in the art that the foregoing and otherchanges in form and details may be made therein without departing fromthe spirit and scope ofthe invention.

We claim:

I. A moving display gas panel display system comprising:

a display housing having a viewing window;

a first plurality of parallel conductors disposed behind the viewingwindow;

a second plurality of parallel conductors substantially perpendicular tothe first plurality, and intersecting therewith to form a display pointat each intersection;

translating means for translating at least the second plurality ofconductors past the display window to create a moving display;-

an ionizeable gas in the vicinity of the display points for supporting aglow discharge;

writing means for activating selected display points along conductors ofthe second plurality to display 1 information, and;

energizing means connected between the first and second conductors tosustain a glow discharge in the ionizeable gas at activated displaypoints.

2. The apparatus of claim 1 where the second cohductors are separatedfrom the first conductors by an insulating layer which moves with thesecond conductors.

3. The apparatus of claim 1 wherein:

the tranlating means comprises an endless belt and a drive means forrevolving the belt, and;

the second plurality of parallel conductors are mounted on the endlessbelt.

4. The apparatus of claim 3 wherein:

the first set of parallel conductors is mounted on the inside of thedisplay window, and;

the display housing is gas tight for containing the ionizeable gas.

5. The apparatus of claim 3 wherein the writing means comprises:

a plurality of writing electrodes, one associated with each conductor inthe first set;

pulse generating means for supplying ignition pulses to the writingelectrodes, and;

control means for selectively connecting the pulse generating means tothe writing electrodes to selectively activate display points on thebelt.

6. The apparatus of claim 5 wherein the energizing means applies asustaining voltage between the first and second pluralities ofconductors to sustain a glow discharge in the ionizeable gas.

7. The apparatus of claim 5 further comprising:

erase means for deactiving display points prior to writing newinformation onto the display.

8. The apparatus of claim 5 further comprises:

timing means for controlling the pulse generator to restrict theapplication of ignition pulses to the writing electrodes to times when aconductor from the second plurality is in alignment with the electrodes.

9. The apparatus of claim 8 wherein the timing means comprises:

sense means for sensing alignment between a conductor of the secondplurality and the writing electrodes, and;

timing control means responsive to the sense means for triggering thepulse generating means.

10. The apparatus of claim 9 wherein the first plurality of conductorsis aligned parallel to the direction of motion of the display.

11. A moving display gas panel display system comprising:

a gas tight display housing having a viewing window and containing anionizeable gas;

a first plurality of parallel conductors mounted on the inside of thedisplay window and parallel to the direction of motion of the display;

a second plurality of parallel conductors substantially perpendicular tothe first plurality, a point of closest approach of a conductor from thefirst plurality of conductors to a conductor from the second pluralityof conductors being referred to as a display point;

a driven endless belt supporting the second set of conductors formovement past the window to create a moving display, the conductorsbeing aligned perpendicular to the direction of motion of the belt andthe side of the second conductors belt; energizing means connectedbetween the two sets of conductors to supply a sustaining voltage tosustain a glow discharge between the first plurality of conductors andthe activated display points on the moving belt; sense means for sensingalignment between a conductor of the second plurality and the writingelectrodes, and; timing means responsive to the sense means fortriggering the pulse generating means to apply ignition pulses to thewriting electrodes while the writing electrodes are aligned with aconductor from the second plurality, and; an erase roller fordeactivating previously activated display points prior to writing newinformation. 12. A method of operating a gas panel display systemcomprising the steps;

applying an ignition voltage between a writing electrode exposed to anionizeable gas and an insulator exposed to the ionizeable gas to ionizethe gas between the electrode and the insulator; retaining a charge onthe insulator as a result of the ionization to activate that point onthe insulator; applying a sustaining voltage to a conductor exposed tothe ionizeable gas in the vicinity of the insulator to cause the gas inthe vicinity of any activated points on the insulator to ionize;reversing the sign of the charge on the insulator each time theionizeable gas is ionized by the sustaining voltage to retain theactivation of the point on the insulator. 13. The method of claim 9further comprising the step of moving the insulator past the conductorwhich is exposed to the ionizeable gas, thereby moving the display.

1. A moving display gas panel display system comprising: a displayhousing having a viewing window; a first plurality of parallelconductors disposed behind the viewing window; a second plurality ofparallel conductors substantially perpendicular to the first plurality,and intersecting therewith to form a display point at each intersection;translating means for translating at least the second plurality ofconductors past the display window to create a moving display; anionizeable gas in the vicinity of the display points for supporting aglow discharge; writing means for activating selected display pointsalong conductors of the second plurality to display information, and;energizing means connected between the first and second conductors tosustain a glow discharge in the ionizeable gas at activated displaypoints.
 2. The apparatus of claim 1 where the second conductors areseparated from the first conductors by an insulating layer which moveswith the second conductors.
 3. The apparatus of claim 1 wherein: thetranlating means comprises an endless belt and a drive means forrevolving the belt, and; the second plurality of parallel conductors aremounted on the endless belt.
 4. The apparatus of claim 3 wherein: thefirst set of parallel conductors is mounted on the inside of the displaywindow, and; the display housing is gas tight for containing theionizeable gas.
 5. The apparatus of claim 3 wherein the writing meanscomprises: a plurality of writing electrodes, one associated with eachconductor in the first set; pulse generating means for supplyingignition pulses to the writing electrodes, and; control means forselectively connecting the pulse generating means to the writingelectrodes to selectively activate display points on the belt.
 6. Theapparatus of claim 5 wherein the energizing means applies a sustainingvoltage between the first and second pluralities of conductors tosustain a glow discharge in the ionizeable gas.
 7. The apparatus ofclaim 5 further comprising: erase means for deactiving display pointsprior to writing new information onto the display.
 8. The apparatus ofclaim 5 further comprises: timing means for controlling the pulsegenerator to restrict the application of ignition pulses to the writingelectrodes to times when a conductor from the second plurality is inalignment with the electrodes.
 9. The apparatus of claim 8 wherein thetiming means comprises: sense means for sensing alignment between aconductor of the second plurality and the writing electrodes, and;timing control means responsive to the sense means for triggering thepulse generating means.
 10. The apparatus of claim 9 wherein the firstplurality of conductors is aligned parallel to the direction of motionof the display.
 11. A moving display gas panel display systemcomprising: a gas tight display housing having a viewing window andcontaining an ionizeable gas; a first plurality of parallel conductorsmounted on the inside of the display window and parallel to thedirection of motion of the display; a second plurality of parallelconductors substantially perpendicular to the first plurality, a pointof closest approach of a conductor from the first plurality ofconductors to a conductor from the second plurality of conductors beingreferred to as a display point; a driven endless belt supporting thesecond set of conductors for movement past the window to create a movingdisplay, the conductors being aligned perpendicular to the direction ofmotion of the belt and the side of the second conductors toward thefirst conductors being insulated from the ionizeable gas; a plurality ofwriting electrodes for igniting gas discharges to activate selectedpoints on the endless belt, there being one writing electrode for eachconductor in the first set, and the writing electrodes being alignedalong a line parallel to the conductors of the second set; pulsegenerating means for supplying ignition pulses to the writing electrodesto activate selected display points; control means for selectivelyconnecting the pulse generating means to the writing electrodes toactivate the selected display points on the endless belt; energizingmeans connected between the two sets of conductors to supply asustaining voltage to sustain a glow discharge between the firstplurality of conductors and the activated display points on the movingbelt; sense means for sensing alignment between a conductor of thesecond plurality and the writing electrodes, and; timing meansresponsive to the sense means for triggering the pulse generating meansto apply ignition pulses to the writing electrodes while the writingelectrodes are aligned with a conductor from the second plurality, and;an erase roller for deactivating previously activated display pointsprior to writing new information.
 12. A method of operating a gas paneldisplay system comprising the steps; applying an ignition voltagebetween a writing electrode exposed to an ionizeable gas and aninsulator exposed to the ionizeable gas to ionize the gas between theelectrode and the insulator; retaining a charge on the insulator as aresult of the ionization to activate that point on the insulator;applying a sustaining voltage to a conductor exposed to the ionizeablegas in the vicinity of the insulator to cause the gas in the vicinity ofany activated points on the insulator to ionize; reversing the sign ofthe charge on the insulator each time the ionizeable gas is ionized bythe sustaining voltage to retain the activation of the point on theinsulator.
 13. The method of claim 9 further comprising the step ofmoving the insulator past the conductor which is exposed to theionizeable gas, thereby moving the display.